Hacklet 19 – Ham Radio

October 17, 2014 by Adam Fabio 20 Comments

Amateur, or ham radio operators have always been hackers. For much of the early 1900’s, buying a radio was expensive or impossible. Hams would build their own rigs, learning electronics and radio theory along the way. Time moves on, but hams keep hacking. Today we’re highlighting some of the best ham radio projects on Hackaday.io!

We start with [DainBramage1991] and his very practical RTL-SDR With Upconverter and Case. [DainBramage1991] fell in love with his low-cost RTL software defined radio dongle. He even added a Ham-It-Up upconverter to cover HF bands. The only problem was RF noise. the Realtek USB sticks tend to have little or no filtering, which means they are very susceptible to noise. [DainBramage1991] used the time-honored technique of insulating with copper clad board. Bits of PCB hold the RTL-SDR and upconverter in place. More PCB separates the two boards. Everything goes into a steel enclosure which keeps that unwanted RF at bay.

Next up is [Ryan Miller’s aka KG7HZQ]’s ham radio fox hunt attenuator. Ham radio fox hunt’s don’t involve baying dogs or horses. In this case a fox hunt is a contest to find hidden low power transmitters. If you’ve never tried one, it’s a heck of a lot of fun. One of the challenges with a fox hunt is to find the direction to the transmitter when you’re very close. Even with directional antennas, reflections and swamped receivers make it hard to figure out just where the transmitter is. The solution is an attenuator, which simply reduces the signal to a more reasonable value. [Ryan] also used copper clad PCB for his circuit. Since the attenuator parts are soldered directly to the PCB, this is more of a Manhattan style design. Two ceramic 1k pots help him achieve his goal of near perfect linear attenuation. We’re betting this attenuator will help [Ryan] win some contests!

Who says amateur radio won’t take you places? It may well be taking [Michael R Colton] to space! [Michael’s] project PortableSDR is one of the five finalists in The Hackaday Prize. We covered Michael earlier in the contest. PortableSDR started as a ham radio project: a radio system which would be easy for hams to take with them on backpacking trips. It’s grown into so much more now, with software defined radio reception and transmission, vector network analysis, antenna analysis, GPS, and a host of other features. We seriously love how [Michael] optimized a small LCD for waterfall display, tuning, and bandpass filter adjustment.

[W5VO] is working on an Ethernet to Radio Adapter. Every foot of coax in a radio system loses signal. Connections are even worse. It can all add up to several dB loss. [W5VO] wants to put an SDR at the antenna feed-point. With the signal path minimized, more watts make it out when transmitting, and more signal gets back to the receiver when listening. The interface between the SDR and host computer will be all digital; Ethernet to be precise. [W5VO] isn’t the first person to do something like this, microwave systems have had the transmitter and LNB at the antenna for years. That doesn’t take away from [W5VO’s] design at all He’s been quiet for a while, but we’re hoping he continues on his design!

Where is everyone else? We’re a bit light on projects this week, but we have a good reason. There just aren’t enough ham radio projects on Hackaday.io! We’re hoping to change that though. Are you an amateur radio enthusiast? Document your project on the site. Get input from other hams and push the envelope! You might even find yourself on the Ham Radio List!

That’s all for this episode of The Hacklet. As always, QRX is next week. Same hack time, same hack channel, bringing you the best of Hackaday.io! 73’s!

The DIY Open Crank Engine Moped

October 16, 2014 by Adam Fabio 50 Comments

Anyone can strap a two-stroke engine on a bicycle to create a moped. But [robinhooodvsyou] has created something infinitely more awesome. He’s built an inverted open crank engine on a 10 speed bicycle. (YouTube link) As the name implies, the engine has no crankcase. The crankshaft, camshaft, and just about everything not in the combustion chamber hangs out in the open where it can be seen and appreciated.

[robinhooodvsyou] started with an air-cooled Volkswagen cylinder. He filled the jug with a piston from a diesel car. Camshaft, flywheel, valves, and magneto are courtesy of an old Briggs and Stratton engine. The cylinder head, crankshaft, pushrods, and the engine frame itself are all homemade.

Being an open crank engine, lubrication is an issue. The crankshaft’s ball bearing is lubricated by some thick oil in a gravity fed cup. Even though the engine is a four-stroke,[robinhooodvsyou] adds some oil to the gas to keep the rings happy. The camshaft and connecting rod use Babbit bearings. While they don’t have an automatic oiling system, they do look pretty well lubricated in the video.

Starting the engine is a breeze. [robinhooodvsyou] created a lever which holds the exhaust valve open. This acts as a compression release. He also has a lever which lifts the entire engine and friction drive off the rear wheel. All one has to do is pedal up to cruising speed, engage the friction drive, then disengage the compression release.

We seriously love this hack. Sure, it’s not a practical vehicle, but it works – and from the looks of the video, it works rather well. The unmuffled pops of that low 4:1 compression engine reminds us of old stationary engines. The only thing we can think to add to [robinhooodvsyou’s] creation is a good set of brakes!

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[Peter] And The Amazing Technicolor Phone Wire Bracelet

October 15, 2014 by Adam Fabio 31 Comments

When a job left him with some extra phone wire, [Peter] didn’t toss it in the scrap pile. He broke out the casting resin and made an awesome bracelet (Imgur link). [Peter] is becoming quite an accomplished jeweler! When we last checked in on him, he was making rings out of colored pencils.

Casting the wire in resin was as simple as building a square form, placing the wires, then filling the form with appropriate amounts of epoxy and hardener. Once the epoxy cured, [Peter] drilled out the center with a sharp Forstner bit. A band saw brought the corners of the block closer to a cylinder.

From there it was over to the lathe, where [Peter] used a jam chuck to hold the bracelet in place. Once he shaped the bracelet [Peter] started wet sanding. It took Lots and lots of sanding both inside and out to finish the bracelet. The result is a mirror smooth finish, with bits of insulation bright copper just popping out of the resin.

One might think that the bracelet would be rough with all that copper, but [Peter] mentions on his Reddit Thread that it feels like plastic, though the bits of copper were “very pokey” before sanding. We’d recommend tossing on a clear coating to protect the exposed copper. Worn on a wrist, all that exposed metal would start oxidizing in no time.

This hack gives us lots of ideas for casting wearable circuits. Some WS2812’s and a teensy would make for a pretty flashy setup! Got an idea for a project? Tell us about in the comments, or post it up on Hackaday.io!

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BORAT: Bathroom Monitor For The Future

October 13, 2014 by Adam Fabio 32 Comments

A recent company move has left [kigster] and his 35 coworkers in a frustrating situation. Their new building only has two single occupancy bathrooms. To make matters worse, the bathrooms are located on two different floors. Heading to one bathroom, finding it occupied, then running upstairs to find the second bathroom also occupied became an all to common and frustrating occurrence at the office.

It was obvious the office needed some sort of bathroom occupancy monitoring system – much like those available on commercial aircraft. [kigster] asked for a budget of about $200 to build such a system. His request was quickly granted it by office management. They must have been on their way to the bathroom at the time.

[kigster] began work on BORAT: Bathroom Occupancy Remote Awareness Technology. The initial problem was detecting bathroom occupancy. The easiest method would be to use door locks with embedded switches, much those used in aircraft. Unfortunately, modifying or changing the locks in a rented office space is a big no-no. Several other human detection systems were suggested and rejected. The final solution was a hybrid. Sonar, Passive Infrared (PIR), and light sensors work in concert to detect if a person is in the bathroom. While we think the final “observer unit” is rather cool looking, we’re sure unsuspecting visitors to the office may be wondering why a two eyed robot is staring at them on the throne.

The display side of the system was easy. The entire system communicates with the venerable nRF24L01+ radio modules, so the display just needed a radio module, an arduino, and a way of displaying bathroom status. Two LED matrices took care of that issue.

We really like this hack. Not only is it a great use of technology to solve a common problem, but it’s also an open source system. BORAT’s source code is available on [kigster’s] github.

Want to know more about BORAT? Kigster is answering questions over on his thread in the Arduino subreddit.

Ghost Gunner Machines Your AR-15

October 12, 2014 by Adam Fabio 193 Comments

Defense Distributed and founder [Cody Wilson] have released Ghost Gunner. Defense Distributed entered the public eye a couple of years ago with The Liberator, the world’s first 3D printed gun. Since anyone with a 3D printer can print a Liberator, it is effectively untraceable. This raised a lot of questions in the media and public eye.

Ghost Gunner is a variation on the untraceable theme. Essentially, Ghost Gunner is a CNC designed for one purpose: final drilling and milling steps for AR-15 lower receivers. The reason for this has to do with federal gun laws in the United States. According to US law, the lower receiver is the actual firearm, and is regulated. But when does a block of aluminum become a lower receiver? Here, US law states that the metal becomes a regulated receiver when the machining operations are more than 80% complete.

Anyone can legally buy a barrel, trigger, stock, upper receiver, and various other parts to build an AR-15. To complete the weapon, they only need to buy an 80% lower receiver and perform the last 20% of the metal work. This work can be performed with everything from a drill press to a milling machine to hand tools. Ghost Gunner partially automates this process, making it easier and faster to complete lower receivers and build weapons.

Defense Distributed calls Ghost Gunner an open source hardware project, though we were unable to find the files available for download at this time. It appears that the slides are made up of MakerSlide or a similar aluminum extrusion. The steppers appear to be standard Nema 17 size.

Defense Distributed says that they’ve been having a hard time keeping up with the Ghost Gunner pre-orders. At $1300 each though, we think a general purpose mill or small CNC would be a better deal.

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Hacklet 18 – Tick Tock, It’s Time For Clocks

October 10, 2014 by Adam Fabio 13 Comments

In three words, Hackers love clocks. Not only do we think that digital watches are still a pretty neat idea, we love all manner of timepieces. This episode of The Hacklet focuses on the clock projects we’ve found over on Hackaday.io.

We start with [rawe] and [tabascoeye], who both put the famous XKCD “now” clock into hardware. [tabascoeye] used a stepper motor in his xkcd world clock. [rawe] didn’t have any steppers handy, so he grabbed a cheap wall clock from Ikea for his xkcd.com/now clock in hardware. The now clock needs a 24 hour movement. Ikea only sells 12 hour movements, so [rawe] hacked in a 555 and some logic to divide the clock’s crystal by two. He’s currently using an EEVblog uCurrent to verify his modified clockwork consumes about half a milliwatt.

Next up is [Craig Bonsignore] and his Touchscreen Alarm Clock. [Craig] got sick of store-bought alarm clocks, so he built his own. Then he modified it, added a few features, and kept building! The current incarnation of the clock has a pretty novel interface: a touchscreen over a bicolor LED matrix. The rest of the clock consists of an Arduino, an Adafruit Wave shield, and a Macetech Chronodot. [Craig] is currently mashing up these open source designs and building a single Arduino shield for his clock.

[Warren Janssens] took the minimalist route with The Iris Clock. Iris is a ring of WS2812 RGB LEDs. The LEDs are mounted behind a wall colored piece of wood in such a way that you can only see their glow on the clock frame and the wall beyond it. This helps a with the eye searing effect WS2812s can have when viewed directly – even when dimmed with PWM. The code is mainly C with some AVR assembly thrown in to control the LEDs. [Warren] has given Iris 8 different time modes, from hour/minute/second to percentage of day with sunrise and sunset markers. With so many modes, the only hard part is knowing how to read the time Iris is displaying!

[David Hopkins] also built a ring clock. His Stargate LED Clock not only tells time, but is a great replica of the Stargate from the TV series. [David] used four Adafruit WS2812 Neopixel segments to build a full 60 RGB LED ring. The Stargate runs on an Arduino nano with a real-time clock chip to keep accurate time. A photoresistor allows the Stargate to automatically dim at night. With some slick programming [David] added everything from a visual hourly “chime” to a smooth fade from LED to LED.

[dehne1] gives us something completely different with The Bendulum Clock. A bendulum is [dehne1’s] own creation consisting of an inverted pendulum built without a pivot. The inverted pendulum swings by bending along its length. In [dehne1’s] design, the bendulum is made out of a spring steel strip rescued from a car windshield wiper. The Bendulum doesn’t have a mechanical escapement, but an electromagnet sensed and driven by an Arduino. The amazing part of this project is that [dehne1] isn’t using a real-time clock chip. The standard 8MHz Arduino resonator is calibrated over various temperatures, then used to calibrate the bendulum itself. The result is a clock that can be accurate within 1 minute each day. [dehne1] mounted his clock inside a custom wood case. We think it looks great, and want one for Hackaday HQ!

We’ve used enough clock ticks for this episode of The Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Still want more? Check out our Timepiece List!

EEVblog Tears Into The White Van Speaker Scam

October 8, 2014 by Adam Fabio 91 Comments

[Dave Jones] shows us just how bad audio equipment can get with his white van speaker scam teardown (YouTube link). Hackaday Prize judge [Dave] has some great educational videos on his EEVblog YouTube channel, but we can’t get enough of his rants – especially when he’s ranting about cheap electronics. Check out his world’s “cheapest” camcorder teardown for a classic example

This week [Dave] is tearing down some white van speaker scam A/V equipment. The White Van Speaker Scam (WVSS) is an international hustle which has been around for decades. A pair of guys in a white van stop you in a parking lot, gas station, or other public area. They tell you they’ve got some brand new A/V equipment in the back of their van that they’ll give you for a “great deal”. The speakers are always in fancy packaging, and have a name that sounds like it could be some sort of high-end audiophile brand worth thousands.

Needless to say anyone who buys this equipment finds they’ve been duped and are now the proud owner of some equipment which only sounds good when hitting the bottom of a dumpster. Coincidentally, a dumpster is exactly where [Dave] found his WVSS equipment.

The case of his “Marc Vincent” surround sound system turned out to be nothing more than thin chipboard hot glued together. The electronics were of such shoddy quality that few words describe them – though [Dave] is always ready to improvise. From the ultra cheap subwoofer driver to the 1990’s era vacuum fluorescent display, everything was built down to the lowest cost while still looking nice from the outside. Even the ground wire was just tack soldered to the frame. We especially liked the three vacuum tubes that weren’t even soldered in. The leads were bent over to hold them onto a PCB, while a blue LED lit the tube from below.

Click past the break to see what [Dave] found inside his “3D Optics” projector.

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